1. Field of the Invention
The present invention relates to a robot or the like executing a task by making autonomous motions.
2. Description of the Related Art
Trials have been made on a robot by applying various functions such as environment-recognizing function or autonomous moving function to the robot so as to make it execute tasks such as transporting luggage, locomotive road-guiding and the like. When there are a plurality of robots having such functions present in an environment, it is necessary to construct an execution plan to assign tasks to appropriate robots from the viewpoint of performing the tasks efficiently. Thus, there has been disclosed a technical approach for assigning each task to an appropriate robot according to a priority level or an execution cost of each task (refer to Japanese Patents Laid-open No. 2005-324278 and No. 2006-326703).
However, generally, it is necessary to execute a new unscheduled task, or a state of a task may vary, for example, a content of a scheduled task may be altered. Also, it is considerable that a task may vary from an unassigned state to an assigned state of being executed. Moreover, a state of a robot may vary, for example, the robot may change its position when executing a task. Thus, when the state of a task varies, it is impossible to make each robot execute the task efficiently if the state of each robot is not known correctly. In this regard, central controlling the states of robots in a server may be raised as one of solutions.
Nevertheless, due to increased communication information amount between the server and the robots and the heavy information processing load for recognizing the states of the plurality of robots controlled by the server, the states of the robots may vary massively during the information communication and the information processing, and consequently, it is possible that an execution instruction for a task issued from the server to each robot is inappropriate from the viewpoint of performing the task efficiently.